1. Field of the Invention
The present invention relates to a rapid prototyping process and an apparatus for performing the same, and more particularly, to an intermittent material feed type variable-lamination rapid prototyping process and apparatus using a linear thermal cutting system, wherein sheet materials are intermittently fed and then processed based on cutting operation data, the materials are precisely cut and processed into unit shaped-sheets by using a 4 degree-of-freedom linear thermal cutting system that can be controlled in respective axis directions during the processing, and the unit shaped-sheets are sequentially laminated and bonded one above another, thereby prototyping a precise product in a relatively short period of time.
2. Description of the Related Art
Generally, a rapid prototyping technology means a process of directly forming materials such as pulp sheets, wax, synthetic resin and metal into a 3-dimensional prototype or mold based on 3-dimensional computer aided design (CAD) data. Recently, the materials for use in the process are expanded to metal powder, metal wires and the like.
The existing rapid prototyping processes are largely classified into two types: a curing process of forming a 3-dimensional shape by irradiating and curing a liquid material with a laser beam, and a process of forming a desired shape by bonding granular or stratified solid materials. Stereo lithography (hereinafter, abbreviated as xe2x80x9cSLAxe2x80x9d) falling within the former type is a process of continuously laminating layers one by one by selectively irradiating and curing a liquid photo polymer contained in a container with the laser beam.
The stereo lithography is further divided into two types: a process of locally irradiating the material with the laser beam, and a process of irradiating one of the layers at one time using an ultraviolet lamp. The stereo lithography is a commercial rapid prototyping process that is conventionally used.
However, there is a problem in that the photo polymer solidified during the process is contracted upon curing thereof and thus a warp phenomenon occurs. Further, if a part having any projection is manufactured, an additional support is required for prevention of sagging of the projection of the solidified photo polymer. Moreover, since the photo polymer used as the material has a relatively low strength, there is a problem in that it has a limitation on use for functional products.
Meanwhile, among the conventional rapid prototyping processes, there is a process of forming a desired shape by using powder materials. This process is divided into a selective laser sintering process and a 3-dimensional printing process.
According to the selective laser sintering process, a product is manufactured by applying a synthetic resin powder material and irradiating it with the laser beam so that the powder can be bound. Furthermore, a metallic part or mold can be manufactured by applying iron powder onto a surface made of the synthetic resin.
However, since the manufacture of the metallic part or mold requires a post-treatment such as sintering and involves the contraction resulting from thermal deformation during the post-treatment, there is a problem in that manufacturing accuracy is generally deteriorated.
According to the 3-dimensional printing process, a product is manufactured by selectively sprinkling a liquid binder on applied powder. As for the powder, ceramic powder for use in investment casting and a starch-based powder material are utilized. This process also inevitably requires a post-treatment for increasing the density and strength of the product and has a problem in that the contraction due to the thermal deformation occurs.
In addition, as for further rapid prototyping processes, there are a laminated object manufacturing process (LOM) and a fused deposition manufacturing process (FDM). According to the laminated object manufacturing process, a product is manufactured by repeating operations of bonding laminated pulp sheets using heated rollers and then cutting the bonded pulp sheets using a laser.
Although this process has an advantage in that operating costs can be reduced owing to the use of the pulp sheets, there is a problem in that it takes relatively much time to separate the manufactured product.
According to the fused deposition manufacturing process, a product is manufactured by fusing a filament-type synthetic resin material by passing it through a heated nozzle similar to an extruding die and then bonding the fused material. However, there is a problem in that surface roughness of the product is relatively deteriorated due to the use of the filament-type material.
The disclosed embodiments of the present invention are directed to an intermittent material feed type variable-lamination rapid prototyping process and apparatus using a linear thermal cutting system, wherein a complicated product can be more rapidly and precisely manufactured by controlling variable widths and lengths of materials during processing of the materials.
The embodiments of the invention provide an intermittent material feed type variable-lamination rapid prototyping process and apparatus using a linear thermal cutting system, wherein a plurality of materials having different thicknesses can be intermittently fed.
The foregoing is obtained by an intermittent material feed type variable-lamination rapid prototyping apparatus using a linear thermal cutting system, comprising a collapsible leg with elastic bodies installed at link-connected intersections for supporting sheet materials stacked on the collapsible leg; a friction roller for feeding the supported materials onto a conveyor belt engaged with and simultaneously driven with the friction roller through gears in a state where the friction roller is in pressure contact with one of the sheet materials; said conveyor belt repeating transfer and standby modes; liftable spacing rods installed on both sides of the width of the conveyor belt for lifting each sheet material upward from the conveyor belt during the standby mode of the conveyor belt; a linear thermal cutting system for cutting the upward lifted material into a unit shaped-sheet; a computer for electrically controlling an elevated height of the spacing rods and a transfer speed of the conveyor belt and for controlling operations of the linear thermal cutting system in respective axis directions based on cutting operation data; and a prototyping jig for fixing the unit shaped-sheets to form a predetermined shape in such a manner that one sides of the respective unit shaped-sheets are bonded to and laminated on the other sides of other unit shaped-sheets that geometrically correspond thereto.
Further, an intermittent material feed type variable-lamination rapid prototyping process using a linear thermal cutting system is provided that includes the steps of modeling a product using a 3-dimensional computer aided design (CAD) program in a computer, slicing the modeled product into a plurality of sheets using a program for automatically generating cutting paths, obtaining intermediate sections by restoring a profile of the modeled product and then slicing again the modeled product, and generating cutting operation data based on unit shape data produced from the intermediate sections; intermittently feeding sheet materials supported by a collapsible leg onto a conveyor belt by controlling a feeding speed of a friction roller engaged with the conveyor belt through a gear; lifting each sheet material upward from the conveyor belt in parallel with respect to the ground by shutting off electric power to the conveyor belt for transferring the material to stop the transfer of the material and by raising spacing rods; cutting the materials into unit shaped-sheets based on the cutting operation data by controlling operations of the linear thermal cutting system in respective axis directions using a computer; and prototyping a product by sequentially laminating the unit shaped-sheets onto a prototyping jig while bonding one sides of the unit shaped-sheets to the other sides of the other unit shaped-sheets that geometrically correspond thereto.
Here, each sheet material is formed with a plurality of spacing holes at marginal regions thereof so that the spacing rods are fitted into the respective spacing holes to lift the sheet material upward from the conveyor belt.
Preferably, each sheet material has a laminating hole formed in periphery region thereof so that a laminating rod of the prototyping jig can be fitted into the laminating hole in order to secure the unit shaped-sheet in a laminated position.
Further, it is preferred that the linear thermal cutting system includes a rotatable main spindle, a pivotable rod hingedly connected with and pivotable on one end of the main spindle, a pair of translating rods, and a hot wire and wherein one end of said translating rods are respectively linked with each end portion of the pivotable rod and the hot wire is installed between the other ends of the translating rods.
The hot wire is preferably a wire material for radiating electric resistance heat resulting from an electric current applied thereto, or one selected from a group consisting of a CO2 laser and a ruby laser for use in a cutting operation.
Preferably, the laminating rod consists of a plurality of unit pieces, and each piece has one end with female threads formed therein and the other end with complementary male threads formed thereabout so that the pieces can be fastened to one another.